Four glass and glazing companies are being sued by the owners of the Comcast Center in Philadelphia for designing, fabricating and installing what owner Liberty/Comcast 1701 JFK Boulevard L.P. calls a “defective exterior glass curtainwall system” allegedly using the “inherently defective sealant” polyisobutylene (PIB). The complaint, filed in the Philadelphia County Court of Common Pleas on January 23, 2020, states that defects in the system will cause the owner to incur more than $1 million in damages. Comcast Center’s construction was completed in 2008.

Enclos Corp, Viracon, J.E. Berkowitz, Quanex Building Products and general contractor L.F. Driscoll Co. are listed as defendants in the suit. Enclos was responsible for the design, fabrication and installation of the curtainwall system. Viracon and J.E. Berkowitz fabricated the curtainwall’s insulating glass units (IGUs) using a gray PIB primary sealant from Quanex and Truseal Technologies, which Quanex acquired in 2003.

The owner states in the complaint that in January 2018, it became aware of PIB migration in another of its building’s in Philadelphia. Due to the similarity in design between the two buildings’ curtainwall systems, the owner undertook an investigation into approximately 9% of the Comcast Center’s more than 15,000 IGUs to determine if any PIB migration had occurred there. According to the suit, gray PIB sealant in 25% of the sampled IGUs showed evidence of degradation and migration, which the owner claims is representative of the entire façade.

The complaint explains that gray-colored PIB typically requires a UV stabilizer packer and/or anti-oxidants to be added to the sealant to help it resist degradation associated with exposure to sunlight and UV radiation. The molecular degradation of the PIB polymer can lead to a reduction in molecular weight and viscosity, which can cause the sealant to migrate, or drip, from the IGU joint into the vision area, according to the complaint.

“As noted, once PIB migration begins, it is progressive and irreversible, and is substantially likely to lead to the blockage of the vision zone of the IGU and may lead to the failure of the seal on the IGU,” reads the complaint. “The only way to remediate the migrating PIB is to [remove and] replace the affected IGUs, the cost of which is unknown at this time but is reasonably expected to exceed the sum of $1 million.”

The owner is accusing L.F. Driscoll of a breach of contract for not completing work “free from defects.” As Driscoll’s curtainwall subcontractor, the owner states that Enclos was bound to the same contractual performance standards and contract specifications of Driscoll, making it also in breach of contract. The owner also alleges that all defendants breached an implied warranty or merchantability for supplying IGUs and a PIB sealant “unfit for their ordinary purposes.”